No FileSystem for scheme: hdfs,No FileSystem for scheme: file

Why this happened to us

Differents JARs (hadoop-commons for LocalFileSystem, hadoop-hdfs for DistributedFileSystem) each contain a different file called org.apache.hadoop.fs.FileSystem in their META-INFO/servicesdirectory. This file lists the canonical classnames of the filesystem implementations they want to declare (This is called a Service Provider Interface, see org.apache.hadoop.FileSystem line 2116).

When we use maven-assembly, it merges all our JARs into one, and all META-INFO/services/org.apache.hadoop.fs.FileSystem overwrite each-other. Only one of these files remains (the last one that was added). In this case, the Filesystem list from hadoop-commons overwrites the list from hadoop-hdfs, so DistributedFileSystem was no longer declared.

How we fixed it

After loading the hadoop configuration, but just before doing anything Filesystem-related, we call this:

    hadoopConfig.set("fs.hdfs.impl", 
        org.apache.hadoop.hdfs.DistributedFileSystem.class.getName()
    );
    hadoopConfig.set("fs.file.impl",
        org.apache.hadoop.fs.LocalFileSystem.class.getName()
    );

------------------------------------
I‘ve got the similar problem with "java -jar xx.jar" in hadoop-2.0.5-alpha:
java.io.IOException: No FileSystem for scheme: file

but it works well when running with "hadoop jar".

When I add the follow config into core-default.xml and it works with "java
-jar"

<property>
   <name>fs.file.impl</name>
   <value>org.apache.hadoop.fs.LocalFileSystem</value>
   <description>The FileSystem for file: uris.</description>
</property>

<property>
   <name>fs.hdfs.impl</name>
   <value>org.apache.hadoop.hdfs.DistributedFileSystem</value>
   <description>The FileSystem for hdfs: uris.</description>
</property>

So,maybe it is not the problem of missing required dependencies. I don't
why,but it works!